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Uniface Microsoft SQLserver driver

Author: gianni.sandigliano@unifacesolutions.com (gianni)

I am currently fighting with DB concurrency in a Uniface with Microsoft SQL server installation. We experienced some troubles when reading VIEWS mapped to Uniface entities and underlying tables are at same time INSERTED/UPDATED. Suggestions from experts are to lower the lock level applied to select instruction on views using some SQL hints. My question is: latest Uniface driver vs Microsoft SQL server (U4.0 or U5.0) is using or could use WITH (NOLOCK) or better WITH (READPAST) SQL hints when SELECTing on NO UPDATE entities? Thanks for any answer. Gianni

Uniface Microsoft SQLserver driver

Author: gianni.sandigliano@unifacesolutions.com (gianni)

I am currently fighting with DB concurrency in a Uniface with Microsoft SQL server installation. We experienced some troubles when reading VIEWS mapped to Uniface entities and underlying tables are at same time INSERTED/UPDATED. Suggestions from experts are to lower the lock level applied to select instruction on views using some SQL hints. My question is: latest Uniface driver vs Microsoft SQL server (U4.0 or U5.0) is using or could use WITH (NOLOCK) or better WITH (READPAST) SQL hints when SELECTing on NO UPDATE entities? Thanks for any answer. Gianni

Hi all, the short version of a long answer: from SQLserver 2005 is available an initial implementation of the so called "Snapshot isolation level"; this implementation was fully consolidated with SQL Server 2008. "Snapshot isolation level" is enabling at connection level what it was previously implementable only using SQL hints "WITH NOLOCK" or "WITH READPAST"  at instruction level. More informations on "Snapshot isolation level" at: https://msdn.microsoft.com/en-us/library/tcbchxcb.aspx Regards, Gianni


Author: gianni (gianni.sandigliano@unifacesolutions.com)
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